Does fasting one day, as mentioned in the hadith: "Whoever fasts one day in the way of Allah, Allah will distance his face from the Fire by seventy autumns," expiate the sin of seventy autumns in Hell mentioned in the hadith: "Indeed, a man may utter a word, thinking nothing of it, by which he plummets seventy autumns into the Fire"?

The two aforementioned hadiths are authentic. The preponderant view is that good deeds do not expiate major sins, but rather minor ones, based on the Prophet's (peace and blessings be upon him) saying: "The five daily prayers, and Friday prayer to Friday prayer, and Ramadan to Ramadan, are expiations for what is between them, as long as major sins are avoided." Therefore, major sins necessitate a specific repentance. If the words uttered by the person are among the major sins, such as slander and lying, then fasting for days will not expiate them; rather, a specific repentance is required. However, if they are minor sins, then they are effaced by fasting and other good deeds.